Thanks to James for introducing this forum. Finding it useful for queries.
First time I’ve used valve extenders. I read that putting PTFE tape on the inner tube thread gives a tighter seal when pumping up tyre. I’ve managed to inflate the tyre but my gauge doesn’t register the pressure so not sure what the actual bar/psi is. The tyre seems ok, maybe I’ll try the tape. Anyone else experienced this?

@gareth_bevan thanks for asking. We realize that we need instructions and manuals for the valve extenders and more. So thanks for pointing out this common confusion point.

Without seeing your setup, it’s hard to be sure exactly what’s going on, but I think you gave some good clues, so I will try to diagnose and give an answer.

Question: are you using a removable valve core tube? If not then my upcoming diagnosis will certainly be correct.

Question 2: if you are using a removable core, did you remove the core, install the extension then reinstall the core into the extension?

If either of those answers are no, the you have the vale extension installed backwards. It will fit backwards because of common threads and you will be able to pump air into your tire but it’s not the proper installation and you won’t be able to get pressure readings on your gauge or lock your valve shut.

The fix would be to take the necessary steps such that you can answer Yes to my two questions above.

Without the core at the point of contact with your gauge, you have no way of opening the valve and reading the pressure in the tube.

If you have a removable core tube and remove the core, the extender will screw into (not on to the outside of) the tube’s valve stem and the core will screw into the other end of the extender (like it was in the tube’s stem). If you are using a non-removable core, the valve extended will only thread on to the outside of the valve stem on the tube (will only fit one way) and you cannot read the pressure. Actually, there are ways around it, but they are a bit tricky and would need a floor pump with a built in pressure gauge.

I know is sounds a little confusing, but with a deep dish set of wheels, you kind of need the removable core tubes or tubes with long valve stems to make you life easier.

@k200mtbman 'a response is totally accurate. This is a confusing subject and a tutorial video would help a lot. Basically you will want to buy a new tube with a removable core to solve your problems. Let me know if you need any help with that, or anything else. Thanks.

I’m glad I ran into this topic. I too was puzzled with what to do with the supplied valve extenders. I thought I knew how to use them, I guess not.

I opted to just use (Giant)tubes with long enough valves stems to fit the EPIC38-50 wheels. I installed a tube with 60mm stem on the 38mm wheel and an 80mm stem on the 50mm wheel; the 80mm stem was a little long on the 50mm wheel, but the 60mm stem was too short.
I have some new tubes with shorter valve stems lying around, so I may opt to go the valve extender route the next time.

Just ordered my wheels. Very excited. Looking at the thread I was wondering, Hd anyone managed to get a 62mm inner tube on the EPIC 50 rim to work? I am keen to avoid valve extenders but if the 80mm is too long there might be no alternative.

@CWayman thanks for asking. You probably already had things sorted out by our support team, but I figured I’d give some info here. The valve extensions that we currently ship with our wheels just screw on top of an open Presta valve. They look like they are possibly meant to replace the valve core on the tube, but they are not meant for that.

Also one other thing about the valve extensions, and almost every valve extension. You’re going to want to use some Teflon tape on the threads of the valve to get an airtight seal. Or often in a tire patch kit they will include some small latex tubing that you can use as a seal. I know it’s a total pain, and we are working on a solution to include some O-rings or better sealing valve extensions with our wheels in the future.

I roll the valve extenders that have o-rings and I haven’t experienced a problem and use no tape. They aren’t cheap but I prefer those over the cheaper version and using a PTFE or similar tape. Maybe providing an upgrade option would be suitable.

I have this problem too. I have continental tubes. There are 2 threads on the core. One coarser thread is for the valve cap and the finer thread goes into the value stem. The extender thread that goes into the value stem when the core is removed is the coarse thread which won’t fit into the value steam which is expecting the finer thread. And in the extender the internal thread is course, and the valve core will not fit properly because the thread on the valve core is too fine. Any resolutions?

Okay. The extensions will not allow for the proper filling of air with a gauge then and will not allow for the releasing of air either, unless you poke something down in the hole of the carbon wheels.
The best thing is to get alternate thread extenders or get tubes with long stems.